Gear case unit for outboard motors



April 1951 E. c. KIEKHAEFER 2,549,477

I GEAR CASE UNIT FOR OUTBOARD MOTORS Filed May 12, 1947 4 SheetsSheet 1 if]; j

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[/2 zaw April 17, 1951 E. c. KIEKHAEFER 2,549,477

GEAR CASE UNIT FOR OUTBOARD MOTORS Filed May 12, 1947 4 Sheets-Sheet 2 IN VEN TOR.

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GEAR CASE UNIT FOR OUTBOARD MOTORS 4 Sheets-Sheet 3 IN VEN TOR.

j/lorwey Aprifi 17,, 1951 E. c. KIEKHAEFER GEAR CASE UNIT FOR OUTBOARD MOTORS 4 Sheets-Sheet 4 Filed May l2, 1947 INVENTOR.

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Patented Apr. 17, 1951 GEAR CASE UNIT FOR OUTBOARD MOTORS Elmer C. Kiekhaefer, Cedarburg, Wis.

Application May 12, 1947, Serial No. 747,443

This invention relates to outboard motors and has particular reference to the construction of the lower end unit for an outboard motor.

The lower housing of an outboard motor is secured to the lower end of the upper or drive 7 shaft housing, and usually serves to carry the cavitation plate and house the lower end of the vertical drive shaft, the lower gears, the propeller shaft and the water pump. The lower housing has always been constructed of two or more separate castings with the parting line-variously arranged, either vertical or horizontal, or both. Parting lines in'the cast housing have been diiiicult to maintain against leakage and the packing employed ultimately deteriorates and allows dirt and grit to be carried into the housing, particularly under hardv usage.

Another object of the invention is to provide A a lower end housing devoid of parting lines and which is more effectively sealed against infiltration and corrosion.

Another object is to simplify the construction and assembly of the lower end unit.

Another object is to improve the gear alignment and simplify adjustment of the gears in the 7 Claims. (01.115-17) lower end unit, and thereby reduce noise and increase the life of the gears. 'Another object is to prevent possible distortion of the drive shaft bearings, and thereby increase the life of the bearings.

Another object is to simplify the replacement of worn parts and reduce the cost of the parts housing is recessed by the use of collapsible core members in a manner providing a desirable space size for the beveled gears without machining.

Another object is to reduce the unit area thrust load of the propeller upon the thrust bear- 2 ing and to provide a frictionless type of thrust bearing therefor without requiring enlargement of the housing.

Another object is to remove the axial thrust loads from the end bearings for the drive shaft and the propeller shaft.

Other objects and advantages will appear hereinafter in the description of an embodiment of the invention illustrated in the accompanying drawings.

In the drawings:

Figure 1 is a side elevation of an outboard mo- 7 tor embodying the invention;

Fig. 2 is an enlarged vertical section through the lower end unit taken. in-the plane of the drive and propeller shafts; V

Fig. 3 is a similar section showing the ,cast housing prior to assembly of the mechanism therein; I a

Fig. 4 is a transverse vertical section take axially of the drive shaft on line 44 of Fig. 2;

Fig. 5 isan enlarged detail transverse section showing the attachment of the drive gear on the lower end of the vertical drive shaft, taken on line 5-5 of Fig. 4;

Fig. 6 is a detail section takenon line li6 of Fig. 5; V

Fig. 7 is a'detail section taken on line '|-'I of Fig. 5;

Fig. 8 is a front end elevation of the housing;

Fig.9 is a rear end elevation of the housing;

Fig. 10 is a top plan view of the housing;

Fig. 11 is a side elevation of the propeller shaft assembly prior to insertion in the housing; and

Fig. 12 is a transverse section through the pump taken on line l2l2 of Fig. 11.

erably separate just beneath the horizontal anticavitation plate 5 which is integral with the upper housing 3 and is disposed above the propeller 6 to prevent cavitation.

The lower end housing 4 constructed of a single piece is preferably die cast and embodies a cored vertical opening 1 containing the drive shaft 8 and a cored horizontal opening 9 containing the propeller shaft l0 anditsassembly.

The housing 4 is streamlined with a sharp forward. edge I l extending substantially vertically downward throughout the height of the body of the housing and curving rearwardly therebeneath to provide a skeg I? which serves to protect the propeller 8 against weeds and collision with obstructions and also as a rudder. The rear edge 53 of the housing is also sharp and extends substantially vertically above and below the hollow circular torpedo-like body portion I4 which surrounds cored opening 9 and houses the propeller shaft assembly.

The body of the housing 4 above body portion I4 is of sufficient lateral thickness to accommodate the corecl opening I for the vertical drive shaft 8 and its bearings, and is shaped to provide an effective streamlining between edges l I and 53.

The forward end or nose of the torpedo-like body H! merges into the sharp edge I l preferably without requiring a forward curvature of the edge, and the rear end of the body I4 is circular and of sufficient diameter to receive the propeller shaft assembly in assembling the lower end unit.

The hub 5 for propeller 8 has a diameter at its forward end corresponding to the diameter of the rear end of body I4, and is shaped to con tinue the torpedo-like lines of the body rearwardly to the smaller diameter end provided by rounded cap nut which secures the hub 55 on shaft IS.

The major part of the cored opening 9 in body l4 for the propeller shaft assembly is machined cylindrical, there being a shoulder l'fi' facing rearwardly in the wall of the opening for locating the assembly, and threads I8 at the rear end of the body for securing the assembly in place.

The circumferential shoulder i! may be cast and machined in the wall of opening 9, or it may be formed by an insert piece such as a snap ring or other projecting member secured in the wall of the opening near the lower end of the open ing 7. l

The propeller shaft assembly has a beveled gear IS with a sleeve-like hub 28 secured to rotate with shaft H! by the pin 2|.

A radial and thrust bearing 22 preferably of the frictionless ball bearing type is secured on hub 28 and against the rear side of gear is by means of a snap ring 23 dropped into a corresponding circumferential groove in the hub. The outer race of bearing 22 engages the shoulder il' in body 14 and thereby locates the assembly in housing 4.

The propeller shaft assembly also preferably includes a water pump 24, preferably of the cartridge type such as that set forth in the co-- pending application of the present inventor, Serial No. 94,108, filed May 19, 1949 for Underwater Gear Unit for Outboard Motors.

The water pump 24 here illustrated, is of the rotary type, and has a pump housing or casing 25 of cylindrical outer contour to fit into the cylindrical bore of body It with an expansible sealing washer 26 confined in a circumferential recess therein between the pump housing and the wall of opening 9 by any suitable means such as a flanged washer 26 disposed between the pump housing and the outer race of bearing 22.

The casing 25 has a circular recess El extending inwardly from the rear face of the same, and which constitutes a pump chamber having a wall substantially eccentric to the outer contour of the casing and to propeller shaft H3.

The inner wall of casing 25 has a passage 28 leading from the outside of the casing and into the pump chamber 21. The passage is adapted to register with a series of fine ports 29 through the outer wall of body l4 providing for the admittance of water to the pump chamber 2'1.

The inner wall of casing 25 also has a passage 30 extending from the pump chamber 2'! to the upper surface of the casing where it registers with a passage 3| drilled diagonally upward to a vertical bore 32 in the upper body portion of housing 4.

The impeller for the pump illustrated comprises a plurality of circumferentially spaced flexible vanes 33 and a central hub 34 molded or otherwise secured upon the sleeve 35 which is suitably secured on shaft Ill to rotate therewith. The hub 34 may be fitted tightly upon sleeve 35 and the latter may have spline grooves (not shown) to accommodate the fit of the hub and make sure of the rotation of the impeller with the shaft Ill.

The passages 28 and 39 open to chamber 2'! at opposite sides of the pump as determined by a diametric line coincident with the maximum 1 and minimum radii of the pump chamber, with the inlet passage 28 supplying water to the chamber on the side where the vanes 33 are gradually separating and expanding the capacity therebetween, and the discharge passage 30 on the opposite side and near the point of shortest radius of the chamber.

The pump chamber 21 is closed on its inner side by the inner wall of casin 25 which is sealed against the shaft by one or more cup seals 36.

The pump chamber 2'! is closed on its rear side by the rear end plate 3'! which is threaded into the end of body M at threads l8, and which secures the entire propeller shaft assembly in place.

The vertical body of housing 4 has the cored opening l for the shaft 8 machined at its upper end to receive a radial and thrust bearing 39 preferably of the ball bearing type for the shaft, and provide a shoulder 40 upon which the outer race of the bearing rests. A cup seal 4! is provided above the bearing 39 between the outer race and the shaft 8. I

The lower end of the cored opening in the vertical body of housing 4 is bored on a smaller diameter to receive a needle bearing 42 for shaft 8 just above body I4. The bearings 39 and 42 are axially aligned to provide an accurate support for the drive shaft 8.

A beveled drive gear 43 is secured to the lower end of shaft 8 to mesh with gear H) for driving the latter. The securing of gear 43 upon shaft 8 should be simple and free from the usual key, since it must be accomplished inside housing 4 where the workman has access to the parts only through the rear open end of body l4.

In the construction illustrated the lower end of shaft 8 is tapered in diameter at 44 to a short smaller diameter substantially cylindrical end portion &5 which latter has a plurality of longitudinal spline grooves 46 therein cut to a depth at least as great as the extension of the taper.

The gear 43 has a tapered central opening in its hub for fitting onto the end of shaft 8, and a plurality of spline grooves 41 are broached in the smaller diameter portion of the gear, so that the intermediate projections fit into the corresponding grooves 46 on the shaft and secure the gear and shaft together for common rotation.

The gear 43 is secured axially against the taper of shaft 8 by means of cap screw 48 and a lock washer'49 tabbed as shown.

The upper end of housing 4 has two vertically drilled holes for securing the housing to housing 3. For this purpose hole 58 is disposed immediately behind edge H and adjacent the vering 3.

. tical cored opening I, and is adapted to receive a tie rod in theform of stud I threaded into hole 59 at 52 and extending upwardly into hous- The threaded attachment at 52 is disposed intermediate bearings 39 and-42 and preferably spaced'axially from the upper bearing 39 a substantial distance, so that the hole- 50' may be dis- The hole 50 extends downwardly beyond the threads at 52 to open into the cored opening 9. A hole 53 is drilled diagonally to connect hole 50 to cored opening 1 above the needle bearing 42 and below the threads at 52. This construction provides for the circulation of lubricant with which the housing is filled, to bearing 39.

The gear 43 serves as a lubricant pump tendin to centrifugally throw the lubricant outwardly from the lower end of bearing 42, and some of the lubricant passes upwardly through hole 50 and thence through hole 53 into opening I where it may'pass downwardly through the bearing 42. f

The gear chamber and holes and openings referred to are all packed with lubricant after assembly of the unit, by means of a hole in the nose of body I4 to one side of the skeg I2 and which is closed by the screw plug 54.

A suitable air vent hole, which is closed by screw plug 54' at all times except when filling the housing with lubricant, is provided near the topof the housing, preferably just beneath bearing 39.

, All of the bearings are lubricated by means of' the grease packed into the housing, as'described.

A hole 55, corresponding to hole 59, is disposed just forwardly of rear edge l3and adjacent the bore 32 which in turn is disposed to the rear of opening I and adjacent thereto.

A recess 56 in' rear edge I3 is adapted 'to receive a nut 5! registering with hole 55 and into which a tie rod in the form of bolt 58 is threaded downwardly through hole 55 from housing 3 to complete the securing of housings 3 and 4 together.

' A water pipe 59, extends downwardly from housing 3 into bore 32 and has a beveled lower end for registering with passage 3| and receiving water from pump 24'. A seal 69 is provided for pipe 59 at the upper end of housing 4. The shaft 8 has a shoulder 6| which transmits the thrust of gear 43 to bearing 39. A suitable gasket 62 may be provided across the top of the lower housing 4- to seal the same against the upper housing 3. Shims 63 are disposed between the outer race of bearing 22 and shoulder I! to adjust the axial position of gear 59 relative tothe axis of gear 43.

Likewise, shims B4 are disposed above and below the outer race and cap housing for bearing 39, and may be divided by selection to provide any desired thickness of shims between the outer race and shoulder 40 to adjust the vertical position for gear 43. By employing a predetermined total thickness of shims 64 and disposing the complemental part of them above the bearing, as

shown, the bearing does not interfere with the clamping of the two housings 3 and 4 together, and the bearing is always securely clamped between housing 3 and shoulder 40 with the shims selectively disposed therebetween.

The lower end housing described avoids the difficulties arising from the use of multiple piece housings and parting lines.

The construction described provides a simpler assembly of parts, and one which'requires a minimum of labor in placement of individual parts within the housing. The lower end housing may be die cast, in

which case the opening I is cored by means-of a 7 core extending to the bottom end of the smaller diameter portion where needle bearing 42 is later located, and the opening 9 is cored by means of a multi-part collapsible core.

The collapsible inner end of the core for opening 9 is made in two or more sections, the lower section forming a tapered bottom wall 65 for the nose of the opening, as shown, and the upper section forming a, recess 66 for receiving gear 43.

The-recess 6-5 should be sufiiciently smaller in diameter than the inside diameter of the opening at shoulder I! to provide for the removal of the upper core section through the opening.

The construction provides for a substantial clearance between gear 43 and shaft I0, and for a somewhat larger diameter for gear I9 than for gear 43, which is desirable.

In assembling the lower end unit it is desirable to predetermine the amount of shimming necessary for proper adjustment of the gears.

This can be done for shims 63 by employing suitable gauges which will accurately measure the distance between the center line for shaft 8 and shoulder I1, and also the distance between a reference surface of gear I9 and the correspond-- ing shoulder for bearing 22.

It can be done for shims 64 by employing suitable gauges which will accurately measure the distance between the center line for shaft Ill and the shoulder 49 and compare the same to the, distance between a reference surface of gear 43 and shoulder B I.

In this manner the thickness for shims 63 and 64 can be predetermined-and the shimsmay be positioned in the housing 4 prior to insertion of the mechanism.

The next step is to position the needle bearings 38 and 42 in the housing. Stud 5I is then threaded into bore 50.

Bearing 39 is mounted against shoulder 6I on drive shaft 8 and the latter is inserted downwardly through opening 1 until the end of the shaft passes through bearing 42 and bearing 39 is pressed into its corresponding recess and seated against the shims 64 on shoulder 40.

I Gear 43 is then inserted through opening 9 and fitted onto the end of shaft 8 and tab washer 49 and cap screw 48 applied and tightened to secure the gear in place.

The propeller shaft assembly is'made at the benchby first pinning gear I9 on shaft I0, applying bearing 22 to the gear hub and securing the bearing in place by snap ring 23, then applying the pre-assembled pump'cartridge 24 with its seal 26 onto the shaft and against bearing 22, keying sleeve 35 to the shaft'and applying the end plate 31. r

The propeller shaft assembly is inserted through the rear end of body I4 until the shaft I9 enters bearing 38 and gears I9 and 43 are in mesh, and plate 31 is threaded home in the body to effect engagement of shoulder I! by bearing the gear 43 in final position.

a The last step in the assembly of the lower end. 

